/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.dex.file;

import java.util.Collection;
import java.util.TreeMap;

import com.android.dx.rop.cst.Constant;
import com.android.dx.rop.cst.CstBaseMethodRef;
import com.android.dx.util.AnnotatedOutput;
import com.android.dx.util.Hex;

/**
 * Method refs list section of a {@code .dex} file.
 */
public final class MethodIdsSection extends MemberIdsSection {

	/**
	 * {@code non-null;} map from method constants to {@link MethodIdItem}
	 * instances
	 */
	private final TreeMap<CstBaseMethodRef, MethodIdItem> methodIds;

	/**
	 * Constructs an instance. The file offset is initially unknown.
	 * 
	 * @param file
	 *            {@code non-null;} file that this instance is part of
	 */
	public MethodIdsSection(DexFile file) {
		super("method_ids", file);

		methodIds = new TreeMap<CstBaseMethodRef, MethodIdItem>();
	}

	/** {@inheritDoc} */
	@Override
	public Collection<? extends Item> items() {
		return methodIds.values();
	}

	/** {@inheritDoc} */
	@Override
	public IndexedItem get(Constant cst) {
		if (cst == null) {
			throw new NullPointerException("cst == null");
		}

		throwIfNotPrepared();

		IndexedItem result = methodIds.get((CstBaseMethodRef) cst);

		if (result == null) {
			throw new IllegalArgumentException("not found");
		}

		return result;
	}

	/**
	 * Writes the portion of the file header that refers to this instance.
	 * 
	 * @param out
	 *            {@code non-null;} where to write
	 */
	public void writeHeaderPart(AnnotatedOutput out) {
		throwIfNotPrepared();

		int sz = methodIds.size();
		int offset = (sz == 0) ? 0 : getFileOffset();

		if (out.annotates()) {
			out.annotate(4, "method_ids_size: " + Hex.u4(sz));
			out.annotate(4, "method_ids_off:  " + Hex.u4(offset));
		}

		out.writeInt(sz);
		out.writeInt(offset);
	}

	/**
	 * Interns an element into this instance.
	 * 
	 * @param method
	 *            {@code non-null;} the reference to intern
	 * @return {@code non-null;} the interned reference
	 */
	public MethodIdItem intern(CstBaseMethodRef method) {
		if (method == null) {
			throw new NullPointerException("method == null");
		}

		throwIfPrepared();

		MethodIdItem result = methodIds.get(method);

		if (result == null) {
			result = new MethodIdItem(method);
			methodIds.put(method, result);
		}

		return result;
	}

	/**
	 * Gets the index of the given reference, which must have been added to this
	 * instance.
	 * 
	 * @param ref
	 *            {@code non-null;} the reference to look up
	 * @return {@code >= 0;} the reference's index
	 */
	public int indexOf(CstBaseMethodRef ref) {
		if (ref == null) {
			throw new NullPointerException("ref == null");
		}

		throwIfNotPrepared();

		MethodIdItem item = methodIds.get(ref);

		if (item == null) {
			throw new IllegalArgumentException("not found");
		}

		return item.getIndex();
	}
}
